A second Tampa, Florida, police officer shot during an early-morning traffic stop Tuesday has died, authorities said, as a massive manhunt was under way for two suspects.

"Doctors have pronounced Officer David Curtis deceased," Tampa police spokeswoman Laura McElroy said in a statement. "His family has chosen to harvest his organs so he will remain on life support for the next couple of hours while that takes place."

Officer Jeffrey Kocab was pronounced dead at a Tampa hospital after the incident about 2:15 a.m. ET Tuesday. Both officers were 31, according to the department.

Kocab's wife was due to give birth next week, while Curtis leaves behind his wife and four sons, ages 9, 6, 5 and 8 months.

Curtis had pulled over a vehicle and found its male passenger had an outstanding warrant for "minor violations," Tampa Police Chief Jane Castor told reporters Tuesday. Kocab responded to back Curtis up, and "as they put their hands on the suspect, the suspect spun around, pulled a firearm and shot both police officers," she said.

Curtis pulled the car over because it had no license plate, authorities said in a statement. "Officer Curtis determined the passenger was wanted on a worthless check warrant" out of Jacksonville, Florida, the statement said. He called for backup and Kocab arrived. Both officers approached the vehicle on the passenger side.

Officers responding to a 9-1-1 call from a witness found both officers on the ground and began cardiopulmonary resuscitation, police said. Both were taken to Tampa General Hospital. Kocab was pronounced dead shortly after arrival, while Curtis was put on life support and later pronounced dead.

Both Curtis and Kocab were shot in the upper body, Castor said. They were shot at close range, she told reporters, and body armor would not have helped them avoid injury.

Police dogs had tracked the suspect to a location, she said, and door-to-door searches were under way.

"We haven't positively Identified a suspect, but we have a very good suspect in this situation, and there's probably a great deal more to it than just that misdemeanor warrant," Castor said.

"This is an unbelievable tragedy for these families, and for the larger family of TPD, and for the larger family of the city of Tampa," Mayor Pam Iorio said. "Our hearts are just breaking."

Kocab had been with Tampa police for 14 months, police said, and moved through the TPD's training program at an accelerated pace "because of his outstanding police skills."

Castor said he previously was with the Plant City, Florida, police. Curtis has been with the department for three years and eight months, according to McElroy. He previously was a jail deputy with the Hillsborough County Sheriff's Office.

Castor described both men as "solid police officers and outstanding individuals" who both worked the midnight shift. Kocab, she said, was "looking forward to being a father," and Curtis was devoted to his wife and sons.

Police were searching for a red 1994 Toyota Camry connected to the shooting and an African-American male and female, McElroy said. The male was described as being in his mid- to late 20s, about 5 feet 10 inches tall and weighing about 150 to 170 pounds. He is thought to be wearing brown shorts, a white T-shirt, a black vest and white sneakers, police said. No detailed description was available on the woman.

The officers' deaths come nearly a year after Tampa police Cpl. Mike Roberts was killed in the line of duty last August, Florida Attorney General Bill McCollum said in a statement.

"The safety of Tampa residents was the first priority for Officers Kocab and Curtis, and today they selflessly made the ultimate sacrifice to protect their city," the attorney general said. "They will certainly be missed not only by their loved ones, but also by the city they worked to keep safe."

Authorities set up a perimeter around the shooting scene and were conducting "an extensive search for evidence," police said. "The search for the suspects extends statewide. The suspects are considered armed and very dangerous."

Police were asking to be contacted by anyone who witnessed the incident, has information on the suspects or spots the vehicle.

All cops know that their job risks their lives, its a risk they take each time the put on the uniform. Its just stupid to shoot a cop since you know the department will pull every resource they have to catch you ass.